DESCRIPTION (Applicant's Abstract): The proposed investigation addresses an important health care issue for women and their children. The use of antiepileptic drugs (AEDs) in women of childbearing age for epilepsy and for other indications (e.g., pain and psychiatric disorders) is common, but physicians need additional data, which are critical to adequately advise and direct treatment in these women. Animal studies have clearly demonstrated that commonly employed AEDs impair behavioral neurodevelopment. The potential consequences of such cognitive and behavioral deficits in humans are severe in terms of both personal and societal costs. However, controversy exists on the following issue to be addressed by this proposal. Do the most commonly used AEDs have differential effects on neurobehavioral outcomes in children exposed in utero? The primary objective of this study is to differentiate the relative risks/benefits of three major AEDs in the treatment of women with epilepsy in terms of their children's neurobehavioral development after in utero exposure. The study objectives will be addressed by a prospective, parallel-group, cohort design, multi-center investigation enrolling three groups of pregnant women on AED monotherapy (carbamazepine, phenobarbital, and phenytoin). The primary outcome variables are IQ scores of the children and other measures of neurobehavioral development. The results of the study will impact the clinical management of women receiving these medications, and improve the health of their children.